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authorLinus Torvalds <torvalds@linux-foundation.org>2009-08-10 11:48:51 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-08-10 11:48:51 -0700
commitd00aa6695b67a31be2ce5f7464da32c20cb50699 (patch)
tree4e4a2bbd1ab710ddca3bd1a611a6c3e9a00f52f9 /kernel
parentcec36911b5fa4ac342f6de856b12a9f71f84e6e5 (diff)
parent1853db0e02ae4088f102b0d8e59e83dc98f93f03 (diff)
downloadblackbird-op-linux-d00aa6695b67a31be2ce5f7464da32c20cb50699.tar.gz
blackbird-op-linux-d00aa6695b67a31be2ce5f7464da32c20cb50699.zip
Merge branch 'perfcounters-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'perfcounters-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (27 commits) perf_counter: Zero dead bytes from ftrace raw samples size alignment perf_counter: Subtract the buffer size field from the event record size perf_counter: Require CAP_SYS_ADMIN for raw tracepoint data perf_counter: Correct PERF_SAMPLE_RAW output perf tools: callchain: Fix bad rounding of minimum rate perf_counter tools: Fix libbfd detection for systems with libz dependency perf: "Longum est iter per praecepta, breve et efficax per exempla" perf_counter: Fix a race on perf_counter_ctx perf_counter: Fix tracepoint sampling to be part of generic sampling perf_counter: Work around gcc warning by initializing tracepoint record unconditionally perf tools: callchain: Fix sum of percentages to be 100% by displaying amount of ignored chains in fractal mode perf tools: callchain: Fix 'perf report' display to be callchain by default perf tools: callchain: Fix spurious 'perf report' warnings: ignore empty callchains perf record: Fix the -A UI for empty or non-existent perf.data perf util: Fix do_read() to fail on EOF instead of busy-looping perf list: Fix the output to not include tracepoints without an id perf_counter/powerpc: Fix oops on cpus without perf_counter hardware support perf stat: Fix tool option consistency: rename -S/--scale to -c/--scale perf report: Add debug help for the finding of symbol bugs - show the symtab origin (DSO, build-id, kernel, etc) perf report: Fix per task mult-counter stat reporting ...
Diffstat (limited to 'kernel')
-rw-r--r--kernel/perf_counter.c239
1 files changed, 145 insertions, 94 deletions
diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index 868102172aa4..b0b20a07f394 100644
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -2646,7 +2646,6 @@ static void perf_counter_output(struct perf_counter *counter, int nmi,
u64 counter;
} group_entry;
struct perf_callchain_entry *callchain = NULL;
- struct perf_tracepoint_record *tp;
int callchain_size = 0;
u64 time;
struct {
@@ -2715,9 +2714,16 @@ static void perf_counter_output(struct perf_counter *counter, int nmi,
header.size += sizeof(u64);
}
- if (sample_type & PERF_SAMPLE_TP_RECORD) {
- tp = data->private;
- header.size += tp->size;
+ if (sample_type & PERF_SAMPLE_RAW) {
+ int size = sizeof(u32);
+
+ if (data->raw)
+ size += data->raw->size;
+ else
+ size += sizeof(u32);
+
+ WARN_ON_ONCE(size & (sizeof(u64)-1));
+ header.size += size;
}
ret = perf_output_begin(&handle, counter, header.size, nmi, 1);
@@ -2783,8 +2789,21 @@ static void perf_counter_output(struct perf_counter *counter, int nmi,
}
}
- if (sample_type & PERF_SAMPLE_TP_RECORD)
- perf_output_copy(&handle, tp->record, tp->size);
+ if (sample_type & PERF_SAMPLE_RAW) {
+ if (data->raw) {
+ perf_output_put(&handle, data->raw->size);
+ perf_output_copy(&handle, data->raw->data, data->raw->size);
+ } else {
+ struct {
+ u32 size;
+ u32 data;
+ } raw = {
+ .size = sizeof(u32),
+ .data = 0,
+ };
+ perf_output_put(&handle, raw);
+ }
+ }
perf_output_end(&handle);
}
@@ -2849,7 +2868,8 @@ perf_counter_read_event(struct perf_counter *counter,
*/
struct perf_task_event {
- struct task_struct *task;
+ struct task_struct *task;
+ struct perf_counter_context *task_ctx;
struct {
struct perf_event_header header;
@@ -2909,24 +2929,23 @@ static void perf_counter_task_ctx(struct perf_counter_context *ctx,
static void perf_counter_task_event(struct perf_task_event *task_event)
{
struct perf_cpu_context *cpuctx;
- struct perf_counter_context *ctx;
+ struct perf_counter_context *ctx = task_event->task_ctx;
cpuctx = &get_cpu_var(perf_cpu_context);
perf_counter_task_ctx(&cpuctx->ctx, task_event);
put_cpu_var(perf_cpu_context);
rcu_read_lock();
- /*
- * doesn't really matter which of the child contexts the
- * events ends up in.
- */
- ctx = rcu_dereference(current->perf_counter_ctxp);
+ if (!ctx)
+ ctx = rcu_dereference(task_event->task->perf_counter_ctxp);
if (ctx)
perf_counter_task_ctx(ctx, task_event);
rcu_read_unlock();
}
-static void perf_counter_task(struct task_struct *task, int new)
+static void perf_counter_task(struct task_struct *task,
+ struct perf_counter_context *task_ctx,
+ int new)
{
struct perf_task_event task_event;
@@ -2936,8 +2955,9 @@ static void perf_counter_task(struct task_struct *task, int new)
return;
task_event = (struct perf_task_event){
- .task = task,
- .event = {
+ .task = task,
+ .task_ctx = task_ctx,
+ .event = {
.header = {
.type = new ? PERF_EVENT_FORK : PERF_EVENT_EXIT,
.misc = 0,
@@ -2955,7 +2975,7 @@ static void perf_counter_task(struct task_struct *task, int new)
void perf_counter_fork(struct task_struct *task)
{
- perf_counter_task(task, 1);
+ perf_counter_task(task, NULL, 1);
}
/*
@@ -3344,87 +3364,81 @@ int perf_counter_overflow(struct perf_counter *counter, int nmi,
* Generic software counter infrastructure
*/
-static void perf_swcounter_update(struct perf_counter *counter)
+/*
+ * We directly increment counter->count and keep a second value in
+ * counter->hw.period_left to count intervals. This period counter
+ * is kept in the range [-sample_period, 0] so that we can use the
+ * sign as trigger.
+ */
+
+static u64 perf_swcounter_set_period(struct perf_counter *counter)
{
struct hw_perf_counter *hwc = &counter->hw;
- u64 prev, now;
- s64 delta;
+ u64 period = hwc->last_period;
+ u64 nr, offset;
+ s64 old, val;
+
+ hwc->last_period = hwc->sample_period;
again:
- prev = atomic64_read(&hwc->prev_count);
- now = atomic64_read(&hwc->count);
- if (atomic64_cmpxchg(&hwc->prev_count, prev, now) != prev)
- goto again;
+ old = val = atomic64_read(&hwc->period_left);
+ if (val < 0)
+ return 0;
- delta = now - prev;
+ nr = div64_u64(period + val, period);
+ offset = nr * period;
+ val -= offset;
+ if (atomic64_cmpxchg(&hwc->period_left, old, val) != old)
+ goto again;
- atomic64_add(delta, &counter->count);
- atomic64_sub(delta, &hwc->period_left);
+ return nr;
}
-static void perf_swcounter_set_period(struct perf_counter *counter)
+static void perf_swcounter_overflow(struct perf_counter *counter,
+ int nmi, struct perf_sample_data *data)
{
struct hw_perf_counter *hwc = &counter->hw;
- s64 left = atomic64_read(&hwc->period_left);
- s64 period = hwc->sample_period;
+ u64 overflow;
- if (unlikely(left <= -period)) {
- left = period;
- atomic64_set(&hwc->period_left, left);
- hwc->last_period = period;
- }
+ data->period = counter->hw.last_period;
+ overflow = perf_swcounter_set_period(counter);
- if (unlikely(left <= 0)) {
- left += period;
- atomic64_add(period, &hwc->period_left);
- hwc->last_period = period;
- }
+ if (hwc->interrupts == MAX_INTERRUPTS)
+ return;
- atomic64_set(&hwc->prev_count, -left);
- atomic64_set(&hwc->count, -left);
+ for (; overflow; overflow--) {
+ if (perf_counter_overflow(counter, nmi, data)) {
+ /*
+ * We inhibit the overflow from happening when
+ * hwc->interrupts == MAX_INTERRUPTS.
+ */
+ break;
+ }
+ }
}
-static enum hrtimer_restart perf_swcounter_hrtimer(struct hrtimer *hrtimer)
+static void perf_swcounter_unthrottle(struct perf_counter *counter)
{
- enum hrtimer_restart ret = HRTIMER_RESTART;
- struct perf_sample_data data;
- struct perf_counter *counter;
- u64 period;
-
- counter = container_of(hrtimer, struct perf_counter, hw.hrtimer);
- counter->pmu->read(counter);
-
- data.addr = 0;
- data.regs = get_irq_regs();
/*
- * In case we exclude kernel IPs or are somehow not in interrupt
- * context, provide the next best thing, the user IP.
+ * Nothing to do, we already reset hwc->interrupts.
*/
- if ((counter->attr.exclude_kernel || !data.regs) &&
- !counter->attr.exclude_user)
- data.regs = task_pt_regs(current);
+}
- if (data.regs) {
- if (perf_counter_overflow(counter, 0, &data))
- ret = HRTIMER_NORESTART;
- }
+static void perf_swcounter_add(struct perf_counter *counter, u64 nr,
+ int nmi, struct perf_sample_data *data)
+{
+ struct hw_perf_counter *hwc = &counter->hw;
- period = max_t(u64, 10000, counter->hw.sample_period);
- hrtimer_forward_now(hrtimer, ns_to_ktime(period));
+ atomic64_add(nr, &counter->count);
- return ret;
-}
+ if (!hwc->sample_period)
+ return;
-static void perf_swcounter_overflow(struct perf_counter *counter,
- int nmi, struct perf_sample_data *data)
-{
- data->period = counter->hw.last_period;
+ if (!data->regs)
+ return;
- perf_swcounter_update(counter);
- perf_swcounter_set_period(counter);
- if (perf_counter_overflow(counter, nmi, data))
- /* soft-disable the counter */
- ;
+ if (!atomic64_add_negative(nr, &hwc->period_left))
+ perf_swcounter_overflow(counter, nmi, data);
}
static int perf_swcounter_is_counting(struct perf_counter *counter)
@@ -3488,15 +3502,6 @@ static int perf_swcounter_match(struct perf_counter *counter,
return 1;
}
-static void perf_swcounter_add(struct perf_counter *counter, u64 nr,
- int nmi, struct perf_sample_data *data)
-{
- int neg = atomic64_add_negative(nr, &counter->hw.count);
-
- if (counter->hw.sample_period && !neg && data->regs)
- perf_swcounter_overflow(counter, nmi, data);
-}
-
static void perf_swcounter_ctx_event(struct perf_counter_context *ctx,
enum perf_type_id type,
u32 event, u64 nr, int nmi,
@@ -3575,27 +3580,66 @@ void __perf_swcounter_event(u32 event, u64 nr, int nmi,
static void perf_swcounter_read(struct perf_counter *counter)
{
- perf_swcounter_update(counter);
}
static int perf_swcounter_enable(struct perf_counter *counter)
{
- perf_swcounter_set_period(counter);
+ struct hw_perf_counter *hwc = &counter->hw;
+
+ if (hwc->sample_period) {
+ hwc->last_period = hwc->sample_period;
+ perf_swcounter_set_period(counter);
+ }
return 0;
}
static void perf_swcounter_disable(struct perf_counter *counter)
{
- perf_swcounter_update(counter);
}
static const struct pmu perf_ops_generic = {
.enable = perf_swcounter_enable,
.disable = perf_swcounter_disable,
.read = perf_swcounter_read,
+ .unthrottle = perf_swcounter_unthrottle,
};
/*
+ * hrtimer based swcounter callback
+ */
+
+static enum hrtimer_restart perf_swcounter_hrtimer(struct hrtimer *hrtimer)
+{
+ enum hrtimer_restart ret = HRTIMER_RESTART;
+ struct perf_sample_data data;
+ struct perf_counter *counter;
+ u64 period;
+
+ counter = container_of(hrtimer, struct perf_counter, hw.hrtimer);
+ counter->pmu->read(counter);
+
+ data.addr = 0;
+ data.regs = get_irq_regs();
+ /*
+ * In case we exclude kernel IPs or are somehow not in interrupt
+ * context, provide the next best thing, the user IP.
+ */
+ if ((counter->attr.exclude_kernel || !data.regs) &&
+ !counter->attr.exclude_user)
+ data.regs = task_pt_regs(current);
+
+ if (data.regs) {
+ if (perf_counter_overflow(counter, 0, &data))
+ ret = HRTIMER_NORESTART;
+ }
+
+ period = max_t(u64, 10000, counter->hw.sample_period);
+ hrtimer_forward_now(hrtimer, ns_to_ktime(period));
+
+ return ret;
+}
+
+/*
* Software counter: cpu wall time clock
*/
@@ -3715,15 +3759,15 @@ static const struct pmu perf_ops_task_clock = {
void perf_tpcounter_event(int event_id, u64 addr, u64 count, void *record,
int entry_size)
{
- struct perf_tracepoint_record tp = {
+ struct perf_raw_record raw = {
.size = entry_size,
- .record = record,
+ .data = record,
};
struct perf_sample_data data = {
.regs = get_irq_regs(),
.addr = addr,
- .private = &tp,
+ .raw = &raw,
};
if (!data.regs)
@@ -3743,6 +3787,14 @@ static void tp_perf_counter_destroy(struct perf_counter *counter)
static const struct pmu *tp_perf_counter_init(struct perf_counter *counter)
{
+ /*
+ * Raw tracepoint data is a severe data leak, only allow root to
+ * have these.
+ */
+ if ((counter->attr.sample_type & PERF_SAMPLE_RAW) &&
+ !capable(CAP_SYS_ADMIN))
+ return ERR_PTR(-EPERM);
+
if (ftrace_profile_enable(counter->attr.config))
return NULL;
@@ -4285,7 +4337,7 @@ void perf_counter_exit_task(struct task_struct *child)
unsigned long flags;
if (likely(!child->perf_counter_ctxp)) {
- perf_counter_task(child, 0);
+ perf_counter_task(child, NULL, 0);
return;
}
@@ -4305,6 +4357,7 @@ void perf_counter_exit_task(struct task_struct *child)
* incremented the context's refcount before we do put_ctx below.
*/
spin_lock(&child_ctx->lock);
+ child->perf_counter_ctxp = NULL;
/*
* If this context is a clone; unclone it so it can't get
* swapped to another process while we're removing all
@@ -4318,9 +4371,7 @@ void perf_counter_exit_task(struct task_struct *child)
* won't get any samples after PERF_EVENT_EXIT. We can however still
* get a few PERF_EVENT_READ events.
*/
- perf_counter_task(child, 0);
-
- child->perf_counter_ctxp = NULL;
+ perf_counter_task(child, child_ctx, 0);
/*
* We can recurse on the same lock type through:
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